JP3752463B2 - Lightning strike location method, apparatus, system and program - Google Patents

Lightning strike location method, apparatus, system and program Download PDF

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Publication number
JP3752463B2
JP3752463B2 JP2002096237A JP2002096237A JP3752463B2 JP 3752463 B2 JP3752463 B2 JP 3752463B2 JP 2002096237 A JP2002096237 A JP 2002096237A JP 2002096237 A JP2002096237 A JP 2002096237A JP 3752463 B2 JP3752463 B2 JP 3752463B2
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lightning strike
lightning
strike position
temporary
arrival time
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JP2003294824A (en
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成光 岡部
知己 成田
栄 谷口
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Tokyo Electric Power Co Inc
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Tokyo Electric Power Co Inc
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01WMETEOROLOGY
    • G01W1/00Meteorology
    • G01W1/16Measuring atmospheric potential differences, e.g. due to electrical charges in clouds

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  • Environmental & Geological Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • Position Fixing By Use Of Radio Waves (AREA)

Description

【0001】
【発明の属する技術分野】
本発明は、いくつかの受信局への雷電波の到達時間差から落雷位置を標定する標定方法、装置、システム及びプログラムに係り、特に、地形に依存した誤差がない落雷位置標定方法、装置、システム及びプログラムに関するものである。
【0002】
【従来の技術】
この種の落雷位置標定方式は、到来時間差方式と呼ばれる。到来時間差方式では、2地点からの距離の差(電波の到達時間の差と同義)が一定な点の軌跡は双曲線として描かれるという原理を応用して考えられている。図13に示されるように、ある地点に落雷があったとき、落雷により地表付近で発生した電磁波(以下、雷電波という)は、受信局R1,R2,R3へそれぞれT1,T2,T3の到達時間で伝搬する。そのとき、各受信局の時刻計測の同期がとられており、雷電波到達時刻が計測できたなら、雷電波到達時刻のみから相互の到達時間差が求められる。すると、上記の原理より任意の2地点からの距離差が求めた到達時間差に対応している双曲線L12,L23が決定できる。従って、少なくとも3箇所の受信局で雷電波を受信すれば、双曲線L12,L23の交差点Xが雷電波発生地点、つまり落雷位置として標定できる。技術文献として、「落雷位置標定装置(LPAST−T)−電力設備の運用・保守対策支援−,塩田徹,電気現場技術1998.7,特集2落雷対策の最新技術動向,P58」がある。
【0003】
図14に、従来の落雷位置標定システムの構成を示す。図示のように、従来の落雷位置標定システムは、落雷により発生した雷電波を受信する少なくとも3箇所の受信局R1,R2,R3と、各受信局への電波の到達時間差を求め、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出して落雷位置とする落雷位置標定装置H´とを備える。落雷位置標定装置H´は、各受信局R1,R2,R3の水平座標を記憶した受信局座標メモリ3から各受信局R1,R2,R3の水平座標を得て、これを基準に上記原理により落雷位置を標定する。標定結果は、表示装置6に表示され、或いは、メモリに格納され、印刷され、端末へ転送される。
【0004】
なお、受信局は、3箇所あれば上記原理上、十分であるが、4箇所以上設置しておき、適宜な3局を選択して標定に運用してもよい。使用する受信局の位置が落雷位置から遠距離にあるほうが位置標定が正確であるという経験則もあるので、広域にわたり数箇所の受信局を設置するのが通例である。例えば、鹿島、福島、柏崎、松本等の計6箇所に受信局を設置して関中越地域全域の落雷位置標定が実現されている。
【0005】
また、水平距離は、実際には地球の丸みに沿った距離であるが、本明細書では簡単のために2点間を直線で結んだ距離として説明している。
【0006】
【発明が解決しようとする課題】
従来の落雷位置標定システムによって標定された落雷位置には誤差が確認されていた。本出願人は、落雷を受けたことが確認できる鉄塔について、実際に落雷を受けた鉄塔の位置と、そのときに落雷位置標定システムによって標定された落雷位置とのずれを調査した。その結果、特定の地域の鉄塔への落雷に対し、特定の受信局組み合わせにおいて、特定の方向、特定の距離の標定位置ずれが起きていることが判明した。
【0007】
本出願人は、この原因を地形によるものと判断した。即ち、雷電波は、地表面に沿って伝搬する性質がある。地表面に凹凸(起伏ともいう)があれば、伝搬経路は横から見ると直線ではなく凹凸を有することになる。落雷位置から受信局までの雷電波の到達時間は地表面の凹凸に沿った沿面距離に依存するはずであるから、到達時間差は沿面距離で評価するべきである。しかし、従来技術は、地表面を凹凸のない理想的な水平面と見なして上記到来時間差方式を適用しているので、到達時間差は水平距離で評価している。このために、前記した関中越地域の落雷位置標定では受信局から見て山岳地を超えたところにある落雷位置の標定位置ずれが顕著に生じている。
【0008】
そこで、本発明の目的は、上記課題を解決し、地形に依存した誤差がない落雷位置標定方法、装置、システム及びプログラムを提供することにある。
【0009】
【課題を解決するための手段】
上記目的を達成するために本発明の方法は、落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する方法において、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出してその地点を仮の落雷位置とし、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正するものである。
【0010】
前記沿面距離は、地表面の凹凸を雷電波の波長程度の空間波長に平滑化して求めてもよい。
【0011】
また、本発明の装置は、落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する装置において、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出してその地点を仮の落雷位置とする仮標定手段と、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正する補正手段とを備えたものである。
【0012】
前記補正手段は、仮の落雷位置から各受信局までの地表面の凹凸に沿った沿面距離を求める沿面距離算出手段と、この沿面距離と仮の落雷位置から各受信局までの水平距離との比を用いて仮の落雷位置から各受信局までを結ぶ線上の地点から各受信局へ水平電波が到達するべき時間を推定する到達時間推定手段と、この推定到達時間の差を用いて落雷位置を標定しなおす再標定手段とからなってもよい。
【0013】
前記沿面距離算出手段は、標高を含む地図情報を提供する地図データベースを検索して得られた仮の落雷位置から各受信局までを結ぶ線上の標高波形を雷電波の波長程度の空間波長に平滑化して地表面の凹凸を表す沿面線を求め、この沿面線の長さを沿面距離として算出してもよい。
【0014】
前記補正手段は、地図上に縦横所定距離間隔の領域群を想定し、各領域毎に領域内の代表点から各受信局までの沿面距離を考慮した落雷位置の補正量を予め設定した補正量マップと、仮の落雷位置が含まれる領域における補正量を参照し、その補正量を仮の落雷位置に適用して落雷位置を補正するマップ参照手段とからなってもよい。
【0015】
また、本発明のシステムは、落雷により発生した雷電波を受信する少なくとも3箇所の受信局と、各受信局への雷電波の到達時間差を求め、各受信局の座標を基準に前記到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する落雷位置標定装置とを備えた落雷位置標定システムにおいて、前記落雷位置標定装置が請求項3〜6のいずれかに記載の落雷位置標定装置であるものである。
【0016】
また、本発明のプログラムは、落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定するプログラムにおいて、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出して得られた仮の落雷位置を入力する入力手順と、標高を含む地図情報を提供する地図データベースを検索する地図データ検索手順と、その地図情報より仮の落雷位置から各受信局までを結ぶ線上の標高波形を編集し雷電波の波長程度のサンプリング間隔に変換して地表面の凹凸を表す沿面線を求める沿面線抽出手順と、この沿面線を距離積分して沿面距離を求める沿面距離算出手順と、この沿面距離と仮の落雷位置から各受信局までの水平距離との比を用いて仮の落雷位置から各受信局までを結ぶ線上の地点から各受信局へ水平電波が到達するべき時間を推定する到達時間推定手順と、この推定到達時間の差を用いて落雷位置を標定しなおす再標定手順とをコンピュータに実行させるものである。
【0017】
また、本発明のプログラムは、落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定するプログラムにおいて、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出して得られた仮の落雷位置を入力する入力手順と、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正するために、地図上に縦横所定距離間隔の領域群を想定し、各領域毎に領域内の代表点から各受信局までの上記沿面距離で評価した落雷位置の補正量を予め設定した補正量マップから仮の落雷位置が含まれる領域における補正量を参照し、その補正量を仮の落雷位置に適用して落雷位置を補正する補正量マップ参照手順とをコンピュータに実行させるものである。
【0018】
【発明の実施の形態】
以下、本発明の一実施形態を添付図面に基づいて詳述する。
【0019】
図1に示されるように、本発明に係る落雷位置標定システムは、落雷により発生した雷電波を受信する少なくとも3箇所の受信局R1,R2,R3と、各受信局R1,R2,R3への雷電波の到達時間差を求め、各受信局R1,R2,R3の座標を基準に前記到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する落雷位置標定装置Hとを備える。
【0020】
受信局R1,R2,R3は、従来より使用していたものである。詳細は図示しないが、受信局は、電波を入力するアンテナと、電波波形を観測・記憶する波形記憶手段と、その電波波形から落雷発生の特徴部分を抽出する特徴抽出手段と、各受信局間で時刻計測の同期をとる同期手段と、特徴部分が抽出された時刻を落雷発生時刻として検出する時刻検出手段と、その検出時刻を当該受信局への雷電波到達時刻として落雷位置標定装置Hに通知する通知手段とを備える。
【0021】
落雷位置標定装置Hは、各受信局R1,R2,R3の水平座標を基準に各受信局への到達時間差を生じさせるような水平距離差を持つ地点を算出してその地点を仮の落雷位置とする仮標定手段1と、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正する補正手段2とからなる。
【0022】
仮標定手段1は、基本的には既に説明した従来の落雷位置標定装置H´である。つまり、本実施形態では、従来の落雷位置標定装置H´による標定結果を仮の落雷位置としておき、この落雷位置を補正手段2によって補正するという方式を採用している。各受信局R1,R2,R3への雷電波の到達時間差を直接、沿面距離で評価してもよいことは勿論であるが、双曲線を用いた容易な従来方式で仮の落雷位置を求めてから、この仮の落雷位置を基礎にして補正を行う本発明の方式は、実施が簡単で、その標定結果も従来の位置ずれを効果的に改善できることが分かったからである。
【0023】
3は、受信局R1,R2,R3の座標を記憶している受信局座標メモリである。4は、地図データベースである。5は、標高波形、沿面距離、推定到達時間等の演算中に生じる必要なデータを格納する演算用メモリである。6は、標定結果を表示する表示装置である。標定結果は、図示しない印刷装置、記憶装置、端末装置にも送ることができる。
【0024】
補正手段2は、仮の落雷位置から各受信局R1,R2,R3までの地表面の凹凸に沿った沿面距離を求める沿面距離算出手段7と、この沿面距離と仮の落雷位置から各受信局R1,R2,R3までの水平距離との比を用いて仮の落雷位置から各受信局R1,R2,R3までを結ぶ線上の地点から各受信局R1,R2,R3へ水平電波が到達するべき時間を推定する到達時間推定手段8と、この推定到達時間の差を用いて落雷位置を標定しなおす再標定手段9とからなる。
【0025】
沿面距離算出手段7は、標高を含む地図情報を提供する地図データベース4を検索して得られた、仮の落雷位置から各受信局までを結ぶ線上の標高波形を雷電波の波長程度の空間波長に平滑化して地表面の凹凸を表す沿面線を求め、この沿面線の長さを沿面距離として算出するものである。地図データベース4は、例えば、国土地理院数値地図のように既存のものを使用してよい。ただし、国土地理院数値地図は、水平方向50mのサンプリング間隔で標高を提供している。このように既存の地図データベース4から高さ情報を得るときには、後述の理由により、サンプリング間隔を雷電波の波長程度のサンプリング間隔に変換して使用する。例えば、50mのサンプリング間隔のデータを連続40個分平均して2000mのサンプリング間隔のデータとする。もちろん、本発明の落雷位置標定システム用に雷電波の波長程度のサンプリング間隔で地図データベース4を構築しておいてもよい。
【0026】
到達時間推定手段8は、後述する式(1)により推定到達時間を演算するものである。
【0027】
再標定手段9は、推定到達時間から導かれる仮の落雷位置から各受信局R1,R2,R3への水平電波の推定到達時刻を到来時間差方式に適用して落雷位置を標定するものである。再標定手段9には、従来の落雷位置標定装置H´と同じものを使用することができる。仮標定手段1では実際の受信局の到達時刻を入力して位置標定を行うのに対し、再標定手段9では、推定到達時刻を入力して位置標定を行うことになる。図1の実施形態では仮標定手段1と再標定手段9とが別々になっているが、到達時間推定手段8の出力を仮標定手段1に回帰させる形態でも実施は可能である。
【0028】
次に、本発明の原理及び動作を説明する。
【0029】
地上の任意の2地点間には地表面の凹凸がある。例えば、図2に示されるように、仮の落雷位置21から受信局22までを水平直線23で結ぶと、水平距離Lh が得られるが、その間には標高データによる標高波形(沿面線)24を形成することができる。雷電波は、この標高波形24で表される地表面の凹凸に沿って伝搬する。よって、沿面線を距離積分して得られる沿面距離Ls こそが雷電波の到達時間を決定するはずである。
【0030】
これに対して従来方式では、雷電波が水平伝搬すると見なしている(或いは、地表面を凹凸のない理想的な水平面と見なしている)ので、実際より長い到達時間を使って標定していることになる。真の落雷位置は、受信局22から見て仮の落雷位置21より水平距離Lh が近いはずである。また、真の落雷位置は、仮の落雷位置21から受信局22までを結ぶ線上にあるとは限らない。換言すると、受信局22から見た方角が仮の落雷位置21と真の落雷位置とで同じとは限らない。しかし、受信局22から見た方角を変えてしまうと、沿面線22の形状も変わってしまう。
【0031】
そこで、本発明では、方角は変えないで、仮の落雷位置21から受信局22までを結ぶ線上に、落雷位置があると暫定的に考える。この暫定的地点から受信局22へ水平電波が到達するべき時間を推定する。よって、到達時間推定手段8が演算する到達時間補正式は次のようになる。
【0032】
推定到達時間=従来方式到達時間×水平距離Lh /沿面距離Ls …式(1)
ここで、従来方式到達時間は、受信局22が検出した雷電波到達時刻から仮標定手段1が出力した落雷発生時刻を差し引いたものである。沿面距離Ls は沿面距離算出手段7により求める。水平距離Lh は、受信局22の座標と仮の落雷位置21の座標とから求めることができる。
【0033】
到達時間推定手段8は、各受信局R1,R2,R3のそれぞれについて式(1)の演算により推定到達時間を求める。3つの暫定的地点はそれぞれ異なり、互いに相手の推定到達時間を満足しないが、3つの推定到達時間を満足する地点は、別に存在し、この地点が真の落雷位置に近いと思われる。本発明は、補正によって、この地点を求めるものである。つまり、落雷位置で発生した水平電波が推定到達時間後に各受信局R1,R2,R3に受信されたものと仮定する。
【0034】
この推定到達時間に対応する推定到達時刻を計算して再標定手段9に入力する。再標定手段9は、地表面を水平面と見なした到来時間差方式で位置標定を行うものであって、水平電波を各受信局R1,R2,R3が受信した場合には正確な位置標定結果を出すことができるので、落雷位置からの水平電波を各受信局R1,R2,R3が受信したものと仮定した推定到達時刻を入力したことにより、落雷位置が正確に標定されることになる。即ち、仮の落雷位置が真の落雷位置に近くなるよう補正される。
【0035】
次に、沿面距離を求める際の空間波長について説明する。地図データベース4が提供する標高は、水平方向に所定のサンプリング間隔となっている。沿面距離を求める際に、サンプリング間隔が狭いデータを使用する場合とサンプリング間隔が広いデータを使用する場合とでは、算出される沿面距離が異なってしまう。一方、雷電波は、数百kHzの周波数帯に属し、波長は数千mとなる。雷電波の波長以下であるような地表面の凹凸に雷電波が細かく沿って伝搬するとは考えにくい。よって、地表面の凹凸を雷電波の波長程度の空間波長に平滑化しておいて沿面距離を求めるのが妥当と考えられる。
【0036】
これを証明するために、過去の標定結果に対して沿面距離計算時のサンプリング間隔を可変して本発明を適用してみた。図3〜図8は、実際に落雷があった鉄塔の位置(実雷位置という)を原点にとり、各図共通スケールの座標に標定の位置ずれ分をプロットしたものである。図3は、従来方式によるもの。図4〜図8は、順に、サンプリング間隔(空間波長λ)を500m,1000m,2000m,3000m,4000mとして本発明を適用したものである。
【0037】
図3の従来方式では、全体的に原点よりも右側に位置ずれしていると共に、分散が大きい。図4のλ=500mで平滑化した沿面距離を用いたものでは、全体的に原点よりも左上に位置ずれしていると共に、分散が大きい。図5では、全体的な位置ずれが小さく、分散もやや改善されている。図6、即ち、λ=2000mで平滑化したときには、標定結果が原点の近傍によく集まっており、位置ずれは最も小さい。図7(λ=3000m)、図8(λ=4000m)では、全体的に原点よりも僅かに右側に位置ずれしているものの、分散が小さく、従来方式より信頼性が高いと言える。
【0038】
図9には、図3(×印)と図6(●印)とを合成して示した。●印は×印に比べて位置ずれや分散の度合いが小さく、確度の高い落雷位置標定が達成されていることが分かる。
【0039】
以上より、地表面の凹凸を雷電波の波長程度の空間波長に平滑化して沿面距離を求めれば、好ましい補正結果が得られることが証明された。
【0040】
雷電波の波長は、落雷毎に異なるので、落雷を検出した度に受信局で観測した波形から波長解析(周波数解析)して求めてもよい。しかし、本実施形態では、サンプリング間隔をその都度の雷電波波長に合わせて変換に使用するのではなく、知られている平均的な雷電波波長に対応したサンプリング間隔を固定的に使用している。このようにしても、図6〜図8の比較から分かるように、標定結果に極端な誤差は生じない。
【0041】
次に、本発明の別の実施形態を説明する。
【0042】
図10に示されるように、本発明に係る落雷位置標定システムは、図1の実施形態と同様に、落雷により発生した雷電波を受信する少なくとも3箇所の受信局R1,R2,R3と、各受信局R1,R2,R3への雷電波の到達時間差を求め、各受信局R1,R2,R3の座標を基準に前記到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する落雷位置標定装置Hとを備える。そして、受信局R1,R2,R3、受信局座標メモリ3、表示装置6は、図1と同様のものである。
【0043】
落雷位置標定装置Hは、各受信局R1,R2,R3の水平座標を基準に各受信局への到達時間差を生じさせるような水平距離差を持つ地点を算出してその地点を仮の落雷位置とする仮標定手段1と、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正する補正手段2とからなる。仮標定手段1は、図1の実施形態と同様に、従来の落雷位置標定装置H´を用いることができる。
【0044】
補正手段2は、地図上に縦横所定距離間隔の領域群を想定し、各領域毎に領域内の代表点から各受信局までの沿面距離を考慮した落雷位置の補正量を予め設定した補正量マップ11と、仮の落雷位置が含まれる領域における補正量を参照し、その補正量を仮の落雷位置に適用して落雷位置を補正するマップ参照手段12とからなる。
【0045】
この実施形態は、縦横の距離が適宜に短い狭い領域の中であれば、図1の実施形態で仮の落雷位置から補正する補正量が大体同じであるという観点から、領域毎の補正量をマップ上に展開しておき、仮の落雷位置が得られた時点でマップから補正量を引き当てるようにしたものである。図11に示した地図上では、所定の緯度・経度の刻みでメッシュを形成し、各領域Mの中心Pにおける補正量を代表的にその領域Mの補正量としている。補正量マップ11には、領域Mに対応するアドレスに補正量が格納される。マップ参照手段12が当該アドレスから補正量を読み取ることで、図示した仮の落雷位置(稲妻形の先端)X´に対してその領域Mの補正量が適用されることになる。
【0046】
仮の落雷位置が緯度・経度を使った座標で得られる場合、補正量マップ11に設定する補正量も緯度・経度の座標シフト量で表しておく。これにより単純に加算して補正を行うことができる。例えば、緯度・経度の刻みが0.00005度であるような領域分割をしているシステムにおいて、仮の落雷位置X´が北緯36.50003度、東経139.50002度であった場合には、その座標が含まれる領域Mは北緯36.50000度〜36.50005度、東経139.50000度〜139.50005の領域Mである。この領域Mに相当するアドレスを補正量マップ11から検索し、緯度補正量+0.00004度、経度補正量−0.00001度を得たとすると、補正結果は北緯36.50007度、東経139.50001度となる。
【0047】
受信局が4箇所以上設置してあり、適宜な3局を標定に運用する場合、同じ領域に対して複数の補正量を設定しておき、仮の標定に使用した受信局の組み合わせでもって補正量を参照できるようにしておく。
【0048】
なお、メッシュを形成するときの緯度・経度の刻みの大きさは、上記した例に限定されない。刻みを小さくすることで、補正量がより正確になるので、補正量マップ11を構成するハードウェアの容量的な制約がなければ、刻みを小さくするのが好ましい。
【0049】
図10の実施形態では、補正量マップ11さえ準備しておけば、補正量マップ11を参照して加算するだけで簡単に補正ができるので、図1の実施形態よりも落雷位置標定装置Hの構成が簡素で処理時間も短くなる。補正量マップ11は、地図データベース4と受信局R1,R2,R3の座標とがあれば計算によって作成でき、地形の変動や受信局の移設・新設がない限り半永久的に使用することができる。また、補正量マップ11は、落雷位置標定装置Hの内部に組み込んでおく必要はなく、通信回線によりアクセスできるようにしておけばよい。
【0050】
本発明の落雷位置標定方式は、必要な手順をプログラム化しコンピュータに実行させることで実現することができる。即ち、図12に示されるように、3箇所の受信局からそれぞれ雷電波検出時刻を入力する時刻入力手順S1、3箇所の受信局への到達時間差を水平距離差と見なした従来方式の標定手順S2、その標定結果を仮の落雷位置として入力する入力手順S3、地図データベースを検索する地図データ検索手順S4、沿面線を求める沿面線抽出手順S5、沿面距離を求める沿面距離算出手順S6、仮の落雷位置から各受信局までを結ぶ線上の地点から各受信局へ水平電波が到達するべき時間を推定する到達時間推定手順S6、この推定到達時間の差を用いて落雷位置を標定しなおす再標定手順S7などをコンピュータに実行させるプログラムを構成する。時刻入力手順S1、従来方式の標定手順S2、図示しない結果表示手順などは従来からあるプログラムをそのまま利用することができる。
【0051】
また、従来方式の標定手順S2による標定結果を仮の落雷位置として入力する入力手順S3と、補正量マップから補正量を参照して仮の落雷位置を補正する補正量マップ参照手順(図示せず)とをプログラム化しコンピュータに実行させてもよい。
【0052】
補正量マップ11は、このコンピュータの中にある必要はない。このマップ方式の補正用プログラムを使用するユーザは、インターネットを介し、従来の落雷位置標定システムによる落雷位置の通知を受け、さらにマップ参照サービスを受けることで補正が可能である。サービス提供者側は、インターネットで参照可能な補正量マップ11を準備するだけで従来システムを大きく変更することなく少ない投資でサービスを拡充することができる。
【0053】
また、サービス提供者側において、補正を行い、補正済みの落雷位置をユーザに通知するようにしてもよい。
【0054】
【発明の効果】
本発明は次の如き優れた効果を発揮する。
【0055】
(1)沿面距離で到達時間差を評価した落雷位置に補正するので、水平距離で評価している従来方式に見られた位置ずれが解消される。
【0056】
(2)地表面の凹凸を雷電波の波長程度の空間波長に平滑化したので、地表波が実際に伝搬した距離(時間)が標定結果に反映される。
【図面の簡単な説明】
【図1】本発明の一実施形態を示す落雷位置標定システムの構成図である。
【図2】本発明に用いる沿面距離の概念を説明するための地形断面図である。
【図3】従来方式による標定位置の誤差分布図である。
【図4】本発明による標定位置の誤差分布図である。
【図5】本発明による標定位置の誤差分布図である。
【図6】本発明による標定位置の誤差分布図である。
【図7】本発明による標定位置の誤差分布図である。
【図8】本発明による標定位置の誤差分布図である。
【図9】従来方式と本発明を重ねた標定位置の誤差分布図である。
【図10】本発明の一実施形態を示す落雷位置標定システムの構成図である。
【図11】本発明に用いる補正量マップのための領域分割の概念図である。
【図12】本発明の落雷位置標定プログラムの流れ図である。
【図13】到来時間差方式の概念図である。
【図14】従来の落雷位置標定システムの構成図である。
【符号の説明】
1 仮標定手段
2 補正手段
3 受信局座標メモリ
4 地図データベース
5 演算用メモリ
6 表示装置
7 沿面距離算出手段
8 到達時間推定手段
9 再標定手段
11 補正量マップ
12 マップ参照手段
H 落雷位置標定装置
R1、R2、R3 受信局
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an orientation method, apparatus, system, and program for locating a lightning strike position from differences in arrival times of lightning radio waves to several receiving stations, and in particular, a lightning strike location method, apparatus, and system that do not have an error depending on topography. And programs.
[0002]
[Prior art]
This type of lightning location method is called the arrival time difference method. The arrival time difference method is considered by applying the principle that the locus of a point where the difference in distance from two points (synonymous with the difference in arrival time of radio waves) is constant is drawn as a hyperbola. As shown in FIG. 13, when a lightning strike occurs at a certain point, electromagnetic waves (hereinafter referred to as lightning radio waves) generated near the ground due to the lightning strike reach T1, T2, and T3 to receiving stations R1, R2, and R3, respectively. Propagate in time. At that time, the time measurement of each receiving station is synchronized, and if the lightning arrival time can be measured, the mutual arrival time difference can be obtained from only the lightning arrival time. Then, the hyperbola L12 and L23 corresponding to the arrival time difference obtained by the distance difference from any two points based on the above principle can be determined. Therefore, if lightning radio waves are received by at least three receiving stations, the intersection X of the hyperbolic curves L12 and L23 can be determined as a lightning radio wave generation point, that is, a lightning strike position. The technical literature includes “Lightning Locator (LPAST-T)-Support for Operation / Maintenance Measures for Electric Power Facilities, Toru Shioda, Electric Field Technology 19988.7, Special Feature 2 Latest Technology Trends for Lightning Measures, P58”.
[0003]
In FIG. 14, the structure of the conventional lightning strike location system is shown. As shown in the figure, the conventional lightning strike location system calculates at least three receiving stations R1, R2, R3 that receive lightning radio waves generated by lightning strikes, and the arrival time difference of the radio waves to each receiving station. A lightning strike position locating device H ′ that calculates a point having a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of The lightning strike position locating device H ′ obtains the horizontal coordinates of the receiving stations R1, R2, and R3 from the receiving station coordinate memory 3 that stores the horizontal coordinates of the receiving stations R1, R2, and R3. Position the lightning strike. The orientation result is displayed on the display device 6, or stored in the memory, printed, and transferred to the terminal.
[0004]
Note that three receiving stations are sufficient in terms of the above principle. However, four or more receiving stations may be installed, and appropriate three stations may be selected and used for orientation. Since there is an empirical rule that the position is more accurate when the position of the receiving station used is farther from the lightning strike position, it is usual to install several receiving stations over a wide area. For example, lightning strike location in the entire Kanchuetsu area has been realized by installing receiving stations in a total of six locations such as Kashima, Fukushima, Amagasaki, and Matsumoto.
[0005]
Further, the horizontal distance is actually a distance along the roundness of the earth, but in the present specification, it is described as a distance connecting two points with a straight line for the sake of simplicity.
[0006]
[Problems to be solved by the invention]
An error has been confirmed in the lightning strike position determined by the conventional lightning strike location system. The present applicant investigated the difference between the position of the tower that actually received the lightning strike and the position of the lightning strike that was determined by the lightning location system at that time. As a result, it was found that the orientation position shift of a specific direction and a specific distance occurred in a specific combination of receiving stations with respect to a lightning strike to a steel tower in a specific area.
[0007]
The applicant determined that this cause was due to topography. That is, lightning radio waves have the property of propagating along the ground surface. If the ground surface has irregularities (also referred to as undulations), the propagation path has irregularities instead of straight lines when viewed from the side. Since the arrival time of lightning radio waves from the lightning strike position to the receiving station should depend on the creepage distance along the unevenness of the ground surface, the arrival time difference should be evaluated by the creepage distance. However, since the conventional technique considers the ground surface as an ideal horizontal plane without unevenness and applies the above arrival time difference method, the arrival time difference is evaluated by the horizontal distance. For this reason, in the above-described lightning location determination in the Kan-chuetsu area, the lightning position deviation of the lightning location located beyond the mountainous area as viewed from the receiving station is conspicuous.
[0008]
Therefore, an object of the present invention is to provide a lightning strike location method, apparatus, system, and program that solve the above-described problems and have no topographically dependent error.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the method of the present invention calculates a point having a propagation distance difference that causes this arrival time difference from the difference in time when lightning radio waves generated by lightning strikes at least three receiving stations. Then, in the method of locating the lightning strike position, a point having a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of each receiving station is calculated, and the point is set as a temporary lightning strike position. Based on the position, it is corrected to the lightning strike position where the arrival time difference is evaluated by the creeping distance along the unevenness of the ground surface.
[0010]
The creepage distance may be obtained by smoothing unevenness on the ground surface to a spatial wavelength that is about the wavelength of lightning radio waves.
[0011]
In addition, the device of the present invention calculates a point of lightning strike by calculating a point having a propagation distance difference that causes this arrival time difference from the difference in time when lightning radio waves generated by lightning strikes at least three receiving stations. In the apparatus for locating, temporary location means that calculates a point having a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of each receiving station and sets the point as a temporary lightning strike position, and the temporary lightning strike And a correction means for correcting the lightning strike position by evaluating the arrival time difference by the creepage distance along the unevenness of the ground surface based on the position.
[0012]
The correction means includes a creepage distance calculating means for obtaining a creepage distance along the unevenness of the ground surface from the temporary lightning strike position to each receiving station, and a creepage distance and a horizontal distance from the temporary lightning strike position to each receiving station. The arrival time estimation means for estimating the time that the horizontal radio wave should reach each receiving station from the point on the line connecting the temporary lightning strike position to each receiving station using the ratio, and the lightning strike position using the difference in this estimated arrival time It may consist of re-orientation means for re-orienting.
[0013]
The creepage distance calculation means smooths an elevation waveform on a line connecting a temporary lightning strike position to each receiving station obtained by searching a map database providing map information including elevation to a spatial wavelength about the wavelength of a lightning radio wave. The creeping line representing the unevenness of the ground surface may be obtained, and the length of the creeping line may be calculated as the creeping distance.
[0014]
The correction means assumes a group of regions at predetermined vertical and horizontal distance intervals on a map, and sets a correction amount for a lightning strike position in advance that takes into account the creepage distance from a representative point in each region to each receiving station. The map may include map correction means for referring to the correction amount in the region including the temporary lightning strike position and applying the correction amount to the temporary lightning strike position to correct the lightning strike position.
[0015]
Further, the system of the present invention obtains at least three receiving stations that receive lightning radio waves generated by lightning strikes and the arrival time difference of lightning radio waves to each receiving station, and calculates the arrival time difference based on the coordinates of each receiving station. A lightning strike position locating system comprising a lightning strike location locating device that calculates a point having a propagation distance difference that causes a lightning strike position, and the lightning strike location locating device according to any one of claims 3 to 6. It is a lightning location device.
[0016]
Further, the program of the present invention calculates a point of lightning strike by calculating a point having a propagation distance difference that causes this arrival time difference from the difference in time when lightning radio waves generated by lightning strikes at least three receiving stations. In the program for locating, an input procedure for inputting a temporary lightning strike position obtained by calculating a point having a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of each receiving station, and a map including the altitude Map data search procedure to search the map database that provides information, and edit the altitude waveform on the line connecting the temporary lightning strike position to each receiving station from the map information and convert it to a sampling interval of about the wavelength of lightning radio waves. From the creepage line extraction procedure to find the creepage line representing the surface irregularities, the creepage distance calculation procedure to calculate the creepage distance by integrating the creepage distance, and the creepage distance and the temporary lightning strike position. The arrival time estimation procedure for estimating the time that horizontal radio waves should reach each receiving station from the point on the line connecting the temporary lightning strike position to each receiving station using the ratio to the horizontal distance to the receiving station, and this estimated arrival The computer executes a relocation procedure for relocating the lightning strike position using the time difference.
[0017]
Further, the program of the present invention calculates a point of lightning strike by calculating a point having a propagation distance difference that causes this arrival time difference from the difference in time when lightning radio waves generated by lightning strikes at least three receiving stations. In an orientation program, an input procedure for inputting a temporary lightning strike position obtained by calculating a point having a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of each receiving station; In order to correct the lightning strike position based on this temporary lightning strike position, the arrival time difference was evaluated by the creepage distance along the unevenness of the ground surface. Assuming an area group with a predetermined vertical and horizontal distance on the map, each area has a representative point in the area to each receiving station. Evaluated by the creepage distance A correction amount map reference procedure for referring to a correction amount in a region including a temporary lightning strike position from a correction amount map in which the lightning strike position correction amount is set in advance and applying the correction amount to the temporary lightning strike position to correct the lightning strike position. Is executed by a computer.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0019]
As shown in FIG. 1, the lightning strike location system according to the present invention includes at least three receiving stations R1, R2, R3 that receive lightning radio waves generated by lightning strikes, and each receiving station R1, R2, R3. A lightning strike position locating device H that obtains a lightning arrival time difference, calculates a point having a propagation distance difference that causes the arrival time difference with reference to the coordinates of each of the receiving stations R1, R2, and R3, and locates the lightning strike position; Is provided.
[0020]
The receiving stations R1, R2, and R3 have been used conventionally. Although not shown in detail, the receiving station includes an antenna for inputting radio waves, waveform storage means for observing and storing radio wave waveforms, feature extraction means for extracting lightning occurrence feature parts from the radio wave waveforms, and between each receiving station Synchronization means that synchronizes the time measurement at the time, a time detection means that detects the time when the characteristic portion was extracted as a lightning occurrence time, and a lightning strike position locating device H that uses the detection time as a lightning radio wave arrival time at the receiving station. Notification means for notifying.
[0021]
The lightning strike position locating device H calculates a point having a horizontal distance difference that causes a difference in arrival time to each receiving station on the basis of the horizontal coordinates of each receiving station R1, R2, R3, and determines that point as a temporary lightning strike position. And a correction means 2 for correcting the lightning strike position by evaluating the arrival time difference by the creeping distance along the unevenness of the ground surface based on the temporary lightning strike position.
[0022]
The temporary location means 1 is basically the conventional lightning position location device H ′ already described. That is, in this embodiment, a method is adopted in which the orientation result by the conventional lightning strike position locating device H ′ is set as a temporary lightning strike position, and the lightning strike position is corrected by the correction means 2. Of course, it is possible to directly evaluate the arrival time difference of lightning radio waves to each receiving station R1, R2, R3 by the creepage distance, but after obtaining the temporary lightning strike position by a simple conventional method using hyperbola. This is because it has been found that the method of the present invention in which correction is performed based on the temporary lightning strike position is easy to implement, and the positioning result can effectively improve the conventional positional deviation.
[0023]
Reference numeral 3 denotes a receiving station coordinate memory that stores the coordinates of the receiving stations R1, R2, and R3. 4 is a map database. Reference numeral 5 denotes a calculation memory for storing necessary data generated during calculation of altitude waveform, creepage distance, estimated arrival time, and the like. 6 is a display device for displaying the orientation result. The orientation result can also be sent to a printing device, storage device, and terminal device (not shown).
[0024]
The correction means 2 includes a creepage distance calculation means 7 for calculating a creepage distance along the unevenness of the ground surface from the temporary lightning strike position to each receiving station R1, R2, R3, and each receiving station from the creepage distance and the temporary lightning strike position. Horizontal radio waves should reach each receiving station R1, R2, R3 from a point on the line connecting the temporary lightning strike position to each receiving station R1, R2, R3 using the ratio with the horizontal distance to R1, R2, R3. It comprises arrival time estimation means 8 for estimating the time and relocation means 9 for relocating the lightning strike position using the difference between the estimated arrival times.
[0025]
Creeping distance calculation means 7 obtains an altitude waveform on a line connecting a temporary lightning strike position to each receiving station obtained by searching map database 4 that provides map information including altitude as a spatial wavelength about the wavelength of lightning radio waves. The creeping line representing the unevenness of the ground surface is obtained by smoothing and the length of the creeping line is calculated as the creeping distance. As the map database 4, for example, an existing map database such as the Geographical Survey Institute numerical map may be used. However, the Geographical Survey Institute digital map provides elevation at a sampling interval of 50m in the horizontal direction. Thus, when obtaining height information from the existing map database 4, the sampling interval is converted into a sampling interval that is about the wavelength of lightning radio waves and used for reasons described later. For example, the data of the sampling interval of 50 m is averaged for 40 continuous data to obtain data of the sampling interval of 2000 m. Of course, the map database 4 may be constructed at a sampling interval about the wavelength of lightning radio waves for the lightning strike location system of the present invention.
[0026]
The arrival time estimation means 8 calculates the estimated arrival time according to equation (1) described later.
[0027]
The re-location means 9 determines the lightning strike position by applying the estimated arrival times of horizontal radio waves from the temporary lightning strike positions derived from the estimated arrival times to the receiving stations R1, R2 and R3 to the arrival time difference method. The re-location means 9 can be the same as the conventional lightning strike position locating device H ′. The provisional location determination means 1 inputs the actual arrival time of the receiving station and performs position location, whereas the relocation location means 9 inputs the estimated arrival time and performs position location. In the embodiment of FIG. 1, the provisional locating means 1 and the re-location means 9 are separate, but the embodiment can also be implemented in a form in which the output of the arrival time estimation means 8 is returned to the tentative orientation means 1.
[0028]
Next, the principle and operation of the present invention will be described.
[0029]
There is unevenness on the ground surface between any two points on the ground. For example, as shown in FIG. 2, if the horizontal light line 23 connects the temporary lightning strike position 21 to the receiving station 22, the horizontal distance L h In the meantime, an altitude waveform (creeping line) 24 based on altitude data can be formed. Lightning radio waves propagate along the unevenness of the ground surface represented by the altitude waveform 24. Therefore, the creepage distance L obtained by integrating the creepage line. s Only the arrival time of lightning should be determined.
[0030]
On the other hand, in the conventional method, lightning waves are considered to propagate horizontally (or the ground surface is considered to be an ideal horizontal surface with no irregularities), so it is standardized using a longer arrival time than actual. become. The true lightning strike position is a horizontal distance L from the temporary lightning strike position 21 when viewed from the receiving station 22. h Should be close. In addition, the true lightning strike position is not necessarily on the line connecting the temporary lightning strike position 21 to the receiving station 22. In other words, the direction seen from the receiving station 22 is not necessarily the same between the temporary lightning strike position 21 and the true lightning strike position. However, if the direction seen from the receiving station 22 is changed, the shape of the creeping line 22 is also changed.
[0031]
Therefore, in the present invention, the direction is not changed, and it is tentatively considered that there is a lightning strike position on a line connecting the temporary lightning strike position 21 to the receiving station 22. The time for the horizontal radio wave to reach the receiving station 22 from this temporary point is estimated. Therefore, the arrival time correction formula calculated by the arrival time estimation means 8 is as follows.
[0032]
Estimated arrival time = conventional method arrival time × horizontal distance L h / Creepage distance L s ... Formula (1)
Here, the conventional system arrival time is obtained by subtracting the lightning occurrence time output from the temporary orientation means 1 from the lightning radio wave arrival time detected by the receiving station 22. Creepage distance L s Is obtained by creeping distance calculation means 7. Horizontal distance L h Can be obtained from the coordinates of the receiving station 22 and the coordinates of the temporary lightning strike position 21.
[0033]
The arrival time estimation means 8 obtains an estimated arrival time for each of the receiving stations R1, R2, and R3 by the calculation of Expression (1). The three provisional points are different and do not satisfy each other's estimated arrival time, but there are other points that satisfy the three estimated arrival times, and this point seems to be close to the true lightning strike position. The present invention obtains this point by correction. That is, it is assumed that the horizontal radio waves generated at the lightning strike position are received by the receiving stations R1, R2, and R3 after the estimated arrival time.
[0034]
An estimated arrival time corresponding to the estimated arrival time is calculated and input to the re-location means 9. The re-positioning means 9 performs position locating by the time difference of arrival method in which the ground surface is regarded as a horizontal plane, and when each receiving station R1, R2, R3 receives a horizontal radio wave, an accurate position locating result is obtained. Since the estimated arrival time assumed to have been received by the receiving stations R1, R2, and R3 from the lightning strike position is input, the lightning strike position is accurately determined. That is, the provisional lightning strike position is corrected to be close to the true lightning strike position.
[0035]
Next, the spatial wavelength when obtaining the creepage distance will be described. The altitude provided by the map database 4 has a predetermined sampling interval in the horizontal direction. When the creepage distance is obtained, the calculated creepage distance differs depending on whether data having a narrow sampling interval is used or data having a wide sampling interval is used. On the other hand, lightning radio waves belong to a frequency band of several hundred kHz and have a wavelength of several thousand meters. It is unlikely that lightning waves will propagate along the unevenness of the ground surface that is below the wavelength of lightning waves. Therefore, it is considered appropriate to obtain the creepage distance by smoothing the unevenness of the ground surface to a spatial wavelength about the wavelength of lightning radio waves.
[0036]
In order to prove this, the present invention was applied by changing the sampling interval at the time of creepage distance calculation with respect to the past orientation results. 3 to 8 are plots of the position displacement of the orientation on the coordinates of the common scale of each figure, with the position of the steel tower where the lightning strike actually occurred (referred to as the actual lightning position) as the origin. FIG. 3 is based on the conventional method. 4 to 8, the present invention is applied with sampling intervals (spatial wavelength λ) of 500 m, 1000 m, 2000 m, 3000 m, and 4000 m in order.
[0037]
In the conventional system shown in FIG. 3, the position is shifted to the right of the origin as a whole, and the dispersion is large. In the case of using the creepage distance smoothed at λ = 500 m in FIG. 4, the entire position is shifted to the upper left from the origin, and the dispersion is large. In FIG. 5, the overall positional deviation is small and the dispersion is slightly improved. In FIG. 6, that is, when smoothing at λ = 2000 m, the orientation results are often gathered in the vicinity of the origin, and the positional deviation is the smallest. In FIG. 7 (λ = 3000 m) and FIG. 8 (λ = 4000 m), although the position is shifted slightly to the right of the origin as a whole, it can be said that the dispersion is small and the reliability is higher than that of the conventional method.
[0038]
FIG. 9 shows a composite of FIG. 3 (x mark) and FIG. 6 (● mark). ● The mark shows less positional shift and dispersion than the x mark, and it can be seen that lightning strike location with high accuracy has been achieved.
[0039]
From the above, it has been proved that a preferable correction result can be obtained if the creepage distance is obtained by smoothing the unevenness of the ground surface to a spatial wavelength about the wavelength of lightning radio waves.
[0040]
Since the wavelength of lightning radio waves is different for each lightning strike, it may be obtained by wavelength analysis (frequency analysis) from the waveform observed at the receiving station each time a lightning strike is detected. However, in this embodiment, the sampling interval corresponding to the known average lightning wave wavelength is fixedly used instead of being used for conversion in accordance with the lightning wave wavelength of each time. . Even if it does in this way, an extreme error does not arise in the orientation result so that the comparison of FIGS.
[0041]
Next, another embodiment of the present invention will be described.
[0042]
As shown in FIG. 10, the lightning strike location system according to the present invention has at least three receiving stations R1, R2, R3 that receive lightning radio waves generated by lightning strikes, as in the embodiment of FIG. The lightning strike position is determined by calculating the arrival time difference of lightning radio waves to the receiving stations R1, R2, and R3, and calculating the point having the propagation distance difference that causes the arrival time difference based on the coordinates of the receiving stations R1, R2, and R3. And a lightning position locating device H for locating the lightning. The receiving stations R1, R2, and R3, the receiving station coordinate memory 3, and the display device 6 are the same as those in FIG.
[0043]
The lightning strike position locating device H calculates a point having a horizontal distance difference that causes a difference in arrival time to each receiving station on the basis of the horizontal coordinates of each receiving station R1, R2, R3, and determines that point as a temporary lightning strike position. And a correction means 2 for correcting the lightning strike position by evaluating the arrival time difference by the creeping distance along the unevenness of the ground surface based on the temporary lightning strike position. As in the embodiment of FIG. 1, the temporary light-locating means 1 can use a conventional lightning position locating device H ′.
[0044]
The correction means 2 assumes a group of regions at predetermined vertical and horizontal distances on the map, and a correction amount in which a lightning position correction amount is set in advance in consideration of a creeping distance from a representative point in each region to each receiving station. The map 11 includes map reference means 12 that refers to a correction amount in an area including a temporary lightning strike position and applies the correction amount to the temporary lightning strike position to correct the lightning strike position.
[0045]
In this embodiment, if the vertical and horizontal distances are within a suitably short narrow area, the correction amount for each area is set from the viewpoint that the correction amount to be corrected from the temporary lightning strike position in the embodiment of FIG. It is developed on the map, and a correction amount is assigned from the map when a temporary lightning strike position is obtained. On the map shown in FIG. 11, a mesh is formed in increments of predetermined latitude and longitude, and the correction amount at the center P of each region M is typically used as the correction amount for that region M. In the correction amount map 11, the correction amount is stored at an address corresponding to the region M. When the map reference unit 12 reads the correction amount from the address, the correction amount of the region M is applied to the temporary lightning strike position (lightning-shaped tip) X ′ illustrated.
[0046]
When the temporary lightning strike position is obtained by coordinates using latitude and longitude, the correction amount set in the correction amount map 11 is also expressed by the coordinate shift amount of latitude and longitude. Thus, correction can be performed by simply adding. For example, in a system that divides the area such that the latitude / longitude steps are 0.00005 degrees, when the temporary lightning strike position X ′ is 36.50003 degrees north latitude and 139.50002 degrees east longitude, A region M including the coordinates is a region M having a latitude of 36.50000 degrees to 36.50005 degrees north latitude and 139.50000 degrees to 139.50005 degrees east longitude. If the address corresponding to this area M is searched from the correction amount map 11 and the latitude correction amount +0.00004 degrees and the longitude correction amount −0.00001 degrees are obtained, the correction results are 36.50007 degrees north latitude and 139.5001 east longitude. Degree.
[0047]
When four or more receiving stations are installed and three appropriate stations are used for standardization, multiple correction amounts are set for the same area, and correction is performed using the combination of receiving stations used for temporary standardization. Make sure you can see the amount.
[0048]
Note that the size of the latitude / longitude steps when forming the mesh is not limited to the above example. By making the step small, the correction amount becomes more accurate. Therefore, it is preferable to make the step small if there is no capacity limitation of the hardware constituting the correction amount map 11.
[0049]
In the embodiment of FIG. 10, if only the correction amount map 11 is prepared, the correction can be easily performed by simply adding with reference to the correction amount map 11. The structure is simple and the processing time is shortened. The correction amount map 11 can be created by calculation if there is the map database 4 and the coordinates of the receiving stations R1, R2, and R3, and can be used semi-permanently as long as there is no change in terrain or relocation / new installation of the receiving station. Further, the correction amount map 11 does not need to be incorporated in the lightning strike position locating device H, and may be accessible via a communication line.
[0050]
The lightning strike location method of the present invention can be realized by programming necessary procedures and causing a computer to execute them. That is, as shown in FIG. 12, time standard input procedure S1 for inputting lightning radio wave detection times from three receiving stations, respectively, and a conventional method of standardization in which arrival time differences to three receiving stations are regarded as horizontal distance differences. Step S2, an input procedure S3 for inputting the orientation result as a temporary lightning strike position, a map data search procedure S4 for searching a map database, a creepage line extraction procedure S5 for finding a creepage line, a creepage distance calculation procedure S6 for finding a creepage distance, Arrival time estimation step S6 for estimating the time at which horizontal radio waves should reach each receiving station from a point on the line connecting the lightning strike position to each receiving station, and re-establishing the lightning strike position using the difference in estimated arrival times A program for causing the computer to execute the orientation procedure S7 and the like is configured. Conventional programs can be used as they are for the time input procedure S1, the conventional orientation procedure S2, the result display procedure (not shown), and the like.
[0051]
Also, an input procedure S3 for inputting the orientation result of the conventional orientation procedure S2 as a temporary lightning strike position, and a correction amount map reference procedure for correcting the temporary lightning strike position by referring to the correction amount from the correction amount map (not shown). ) May be programmed and executed by a computer.
[0052]
The correction amount map 11 does not need to be in this computer. A user who uses this map type correction program can be corrected by receiving a lightning position notification by a conventional lightning position locating system via the Internet and receiving a map reference service. The service provider side can expand the service with a small investment by preparing the correction amount map 11 that can be referred to on the Internet without greatly changing the conventional system.
[0053]
Further, the service provider side may perform correction and notify the user of the corrected lightning strike position.
[0054]
【The invention's effect】
The present invention exhibits the following excellent effects.
[0055]
(1) Since the lightning strike position where the arrival time difference is evaluated by the creepage distance is corrected, the positional deviation found in the conventional method evaluated by the horizontal distance is eliminated.
[0056]
(2) Since the unevenness of the ground surface is smoothed to a spatial wavelength about the wavelength of lightning radio waves, the distance (time) that the ground wave actually propagated is reflected in the orientation result.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a lightning strike location system showing an embodiment of the present invention.
FIG. 2 is a topographic cross-sectional view for explaining the concept of creepage distance used in the present invention.
FIG. 3 is an error distribution diagram of orientation positions according to a conventional method.
FIG. 4 is an error distribution map of orientation positions according to the present invention.
FIG. 5 is an error distribution map of orientation positions according to the present invention.
FIG. 6 is an error distribution map of orientation positions according to the present invention.
FIG. 7 is an error distribution map of orientation positions according to the present invention.
FIG. 8 is an error distribution map of orientation positions according to the present invention.
FIG. 9 is an error distribution diagram of orientation positions obtained by overlapping the conventional method and the present invention.
FIG. 10 is a configuration diagram of a lightning strike location system showing an embodiment of the present invention.
FIG. 11 is a conceptual diagram of region division for a correction amount map used in the present invention.
FIG. 12 is a flowchart of a lightning strike location program of the present invention.
FIG. 13 is a conceptual diagram of an arrival time difference method.
FIG. 14 is a block diagram of a conventional lightning strike location system.
[Explanation of symbols]
1 provisional orientation means
2 Correction means
3 Receiving station coordinate memory
4 Map database
5 Operation memory
6 Display device
7 Creepage distance calculation means
8 Arrival time estimation means
9 Repositioning means
11 Correction amount map
12 Map reference means
H Lightning locator
R1, R2, R3 receiving station

Claims (9)

落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する方法において、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出してその地点を仮の落雷位置とし、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正することを特徴とする落雷位置標定方法。In a method of calculating a point having a propagation distance difference that causes this arrival time difference from the difference in time when lightning radio waves generated by lightning strikes at least three receiving stations, Calculate a point with a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of the point, and use that point as a temporary lightning strike position, and the creepage distance along the unevenness of the ground surface based on this temporary lightning strike location A lightning strike location method characterized by correcting to the lightning strike position where the arrival time difference was evaluated in step 1. 前記沿面距離は、地表面の凹凸を雷電波の波長程度の空間波長に平滑化して求めることを特徴とする請求項1記載の落雷位置標定方法。2. The lightning strike location method according to claim 1, wherein the creepage distance is obtained by smoothing unevenness on the ground surface to a spatial wavelength about the wavelength of lightning radio waves. 落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する装置において、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出してその地点を仮の落雷位置とする仮標定手段と、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正する補正手段とを備えたことを特徴とする落雷位置標定装置。In a device that calculates a point with a propagation distance difference that causes this arrival time difference from the difference in time when lightning radio waves generated by lightning strikes at least three receiving stations, A location with a horizontal distance difference that causes the arrival time difference with reference to the horizontal coordinate of the position, and a temporary location means that makes the location a temporary lightning strike, and unevenness on the ground surface based on the temporary lightning strike location A lightning strike position locating device comprising correction means for correcting a lightning strike position obtained by evaluating the arrival time difference based on a creepage distance along the line. 前記補正手段は、仮の落雷位置から各受信局までの地表面の凹凸に沿った沿面距離を求める沿面距離算出手段と、この沿面距離と仮の落雷位置から各受信局までの水平距離との比を用いて仮の落雷位置から各受信局までを結ぶ線上の地点から各受信局へ水平電波が到達するべき時間を推定する到達時間推定手段と、この推定到達時間の差を用いて落雷位置を標定しなおす再標定手段とからなることを特徴とする請求項3記載の落雷位置標定装置。The correction means includes a creepage distance calculating means for obtaining a creepage distance along the unevenness of the ground surface from the temporary lightning strike position to each receiving station, and a creepage distance and a horizontal distance from the temporary lightning strike position to each receiving station. The arrival time estimation means for estimating the time that the horizontal radio wave should reach each receiving station from the point on the line connecting the temporary lightning strike position to each receiving station using the ratio, and the lightning strike position using the difference in this estimated arrival time The lightning strike position locating device according to claim 3, further comprising a relocation means for relocating the lightning. 前記沿面距離算出手段は、標高を含む地図情報を提供する地図データベースを検索して得られた仮の落雷位置から各受信局までを結ぶ線上の標高波形を雷電波の波長程度の空間波長に平滑化して地表面の凹凸を表す沿面線を求め、この沿面線の長さを沿面距離として算出することを特徴とする請求項4記載の落雷位置標定装置。The creepage distance calculation means smooths an elevation waveform on a line connecting a temporary lightning strike position to each receiving station obtained by searching a map database providing map information including elevation to a spatial wavelength about the wavelength of a lightning radio wave. 5. A lightning strike position locating device according to claim 4, wherein a creeping line representing the unevenness of the ground surface is obtained and the length of the creeping line is calculated as a creeping distance. 前記補正手段は、地図上に縦横所定距離間隔の領域群を想定し、各領域毎に領域内の代表点から各受信局までの沿面距離を考慮した落雷位置の補正量を予め設定した補正量マップと、仮の落雷位置が含まれる領域における補正量を参照し、その補正量を仮の落雷位置に適用して落雷位置を補正するマップ参照手段とからなることを特徴とする請求項3記載の落雷位置標定装置。The correction means assumes a group of regions at predetermined vertical and horizontal distance intervals on a map, and sets a correction amount for a lightning strike position in advance that takes into account the creepage distance from a representative point in each region to each receiving station. 4. A map and map reference means for referring to a correction amount in a region including a temporary lightning strike position and applying the correction amount to the temporary lightning strike position to correct the lightning strike position. Lightning locator. 落雷により発生した雷電波を受信する少なくとも3箇所の受信局と、各受信局への雷電波の到達時間差を求め、各受信局の座標を基準に前記到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定する落雷位置標定装置とを備えた落雷位置標定システムにおいて、前記落雷位置標定装置が請求項3〜6のいずれかに記載の落雷位置標定装置であることを特徴とする落雷位置標定システム。Find at least three receiving stations that receive lightning radio waves generated by lightning strikes, and determine the arrival time difference of lightning radio waves to each receiving station, and the propagation distance difference that causes the arrival time difference based on the coordinates of each receiving station A lightning strike position locating system comprising a lightning strike location locating device that calculates a location and locating a lightning strike position, wherein the lightning strike location locating device is the lightning strike location locating device according to any one of claims 3 to 6. Characteristic lightning location system. 落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定するプログラムにおいて、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出して得られた仮の落雷位置を入力する入力手順と、標高を含む地図情報を提供する地図データベースを検索する地図データ検索手順と、その地図情報より仮の落雷位置から各受信局までを結ぶ線上の標高波形を編集し雷電波の波長程度のサンプリング間隔に変換して地表面の凹凸を表す沿面線を求める沿面線抽出手順と、この沿面線を距離積分して沿面距離を求める沿面距離算出手順と、この沿面距離と仮の落雷位置から各受信局までの水平距離との比を用いて仮の落雷位置から各受信局までを結ぶ線上の地点から各受信局へ水平電波が到達するべき時間を推定する到達時間推定手順と、この推定到達時間の差を用いて落雷位置を標定しなおす再標定手順とをコンピュータに実行させることを特徴とする落雷位置標定プログラム。In a program that calculates a point with a propagation distance difference that causes this arrival time difference from the difference in time when lightning waves generated by lightning strikes at least three receiving stations, Search for a map database that provides map information including altitude and input procedure for inputting a temporary lightning strike position obtained by calculating a point having a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of The map data search procedure to be performed, and the elevation waveform on the line connecting the temporary lightning strike position to each receiving station from the map information is edited and converted to a sampling interval of about the wavelength of the lightning radio wave, and the creeping line representing the unevenness of the ground surface The creepage line extraction procedure to be calculated, the creepage distance calculation procedure to calculate the creepage distance by integrating the creepage distance, and the ratio of this creepage distance to the horizontal distance from the temporary lightning strike to each receiving station. The lightning strike position is determined using the arrival time estimation procedure for estimating the time that the horizontal radio wave should reach each receiving station from the point on the line connecting the temporary lightning strike position to each receiving station, and the difference between the estimated arrival times. A lightning strike location program that causes a computer to execute a relocation procedure. 落雷により発生した雷電波が少なくとも3箇所の受信局に到達した時間の差から、この到達時間差を生じさせるような伝搬距離差を持つ地点を算出して落雷位置を標定するプログラムにおいて、各受信局の水平座標を基準に前記到達時間差を生じさせるような水平距離差を持つ地点を算出して得られた仮の落雷位置を入力する入力手順と、この仮の落雷位置を基に地表面の凹凸に沿った沿面距離で到達時間差を評価した落雷位置に補正するために、地図上に縦横所定距離間隔の領域群を想定し、各領域毎に領域内の代表点から各受信局までの上記沿面距離で評価した落雷位置の補正量を予め設定した補正量マップから仮の落雷位置が含まれる領域における補正量を参照し、その補正量を仮の落雷位置に適用して落雷位置を補正する補正量マップ参照手順とをコンピュータに実行させることを特徴とする落雷位置標定プログラム。In a program that determines the location of lightning strikes by calculating a point with a propagation distance difference that causes this arrival time difference from the difference in time at which lightning radio waves generated by lightning strikes at least three receiving stations. An input procedure for inputting a temporary lightning strike position obtained by calculating a point having a horizontal distance difference that causes the arrival time difference based on the horizontal coordinate of the ground, and unevenness of the ground surface based on the temporary lightning strike position In order to correct the lightning strike position where the arrival time difference was evaluated based on the creeping distance along the area, assuming the area group at predetermined vertical and horizontal distance intervals on the map, the above creepage from the representative point in the area to each receiving station for each area A correction that corrects the lightning strike position by applying the correction amount to the temporary lightning strike position, referring to the correction amount in the area that includes the temporary lightning strike position from the correction amount map in which the correction amount of the lightning strike position evaluated based on the distance is set in advance. Quantity Lightning position locating program characterized by executing a reference procedure on the computer.
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